Microscopic colitis may be defined as a clinical syndrome, of unknown etiology, consisting of chronic watery diarrhea, with no or minimal changes seen on colonoscopy. Therefore, a definitive diagnosis is only possible by histology. The epidemiological characteristics of this disease have become more elaborate over the past few years, and most of the data has come from Western countries. Microscopic colitis includes two histological subtypes [collagenous colitis (CC) and lymphocytic colitis (LC)] with no differences in clinical presentation and management. Collagenous colitis is characterized by a thickening of the sub epithelial collagen layer which is not seen in LC. The main feature of LC is an increase in the density of intra-epithelial lymphocytes in the surface epithelium.